As an industry we must get rid of seniority to get any power to improve conditions.
I simply can't afford to loose my job (kids, mortgage, loan repayments…) so I won't risk my job. But, if I could join another airline at the same level or higher then everything would change.
If we could move between companies, the companies would have to compete to attract staff. At the moment they only have to attract S/Os and retain them (bond/forgivable loan) for long enough so the golden handcuffs have them locked in.
It is very simple. We are no different to lawyers, doctors and other professions where one's value is a combination of qualification and experience.